From 696caf1d002ff059ddd20fd5eaccd76229c14850 Mon Sep 17 00:00:00 2001 From: Ulrich Weigand Date: Wed, 4 Dec 2013 06:51:11 -0600 Subject: PowerPC64 ELFv2 ABI 2/6: Remove function descriptors This patch adds support for the ELFv2 ABI feature to remove function descriptors. See this GCC patch for in-depth discussion: http://gcc.gnu.org/ml/gcc-patches/2013-11/msg01141.html This mostly involves two types of changes: updating assembler source files to the new logic, and updating the dynamic loader. After the refactoring in the previous patch, most of the assembler source changes can be handled simply by providing ELFv2 versions of the macros in sysdep.h. One somewhat non-obvious change is in __GI__setjmp: this used to "fall through" to the immediately following __setjmp ENTRY point. This is no longer safe in the ELFv2 since ENTRY defines both a global and a local entry point, and you cannot simply fall through to a global entry point as it requires r12 to be set up. Also, makecontext needs to be updated to set up registers according to the new ABI for calling into the context's start routine. The dynamic linker changes mostly consist of removing special code to handle function descriptors. We also need to support the new PLT and glink format used by the the ELFv2 linker, see: https://sourceware.org/ml/binutils/2013-10/msg00376.html In addition, the dynamic linker now verifies that the dynamic libraries it loads match its own ABI. The hack in VDSO_IFUNC_RET to "synthesize" a function descriptor for vDSO routines is also no longer necessary for ELFv2. --- sysdeps/powerpc/powerpc64/dl-irel.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'sysdeps/powerpc/powerpc64/dl-irel.h') diff --git a/sysdeps/powerpc/powerpc64/dl-irel.h b/sysdeps/powerpc/powerpc64/dl-irel.h index d85c614..a500aa6 100644 --- a/sysdeps/powerpc/powerpc64/dl-irel.h +++ b/sysdeps/powerpc/powerpc64/dl-irel.h @@ -50,7 +50,11 @@ elf_irela (const Elf64_Rela *reloc) { Elf64_Addr *const reloc_addr = (void *) reloc->r_offset; Elf64_Addr value = elf_ifunc_invoke(reloc->r_addend); +#if _CALL_ELF != 2 *(Elf64_FuncDesc *) reloc_addr = *(Elf64_FuncDesc *) value; +#else + *reloc_addr = value; +#endif } else __libc_fatal ("unexpected reloc type in static binary"); -- cgit v1.1